FLTK backend

[mgord9518]

Would you be open to having FLTK as an alternative backend? It's very lightweight, themable, stable, cross-platform and may be a good fallback for *nix systems that don't have GTK (and there's existing Zig bindings so implementing should be fairly easy). I'd be happy to work on it if there is any interest

[zenith391]

I'm open to the addition of any new backend although you'd have to understand you would probably be the sole maintainer of it. You can reach me on Matrix if you have any questions.